A "trachytic" unit of alkali-feldspar porphyry, lithic tuff, tuff breccia and pyritic schist is structurally underlain by quartz- sericite schist and chlorite schist with interlayered metasediments of the Devonian to Mississippian part of the Eagle Bay Formation.
Widely spaced quartz stringers carrying galena, sphalerite, pyrite and pyrrhotite occur in the trachyte unit. A sample from a dump assayed 5 per cent zinc, 1.5 per cent lead, 137 grams per tonne silver and 0.7 grams per tonne gold (Annual Report 1923).